Environmental Factors

In order for employees to feel the temperature is appropriate, there must be a correlation between air temperature, exertion and clothing. Sedentary jobs make greater demands than other jobs on air temperature being appropriate because in sedentary situations people are more sensitive to temperature changes.

A requirement for people feeling that the temperature of indoor air is suitable is that there is a balance between the heat generated in the body and the heat it emits.

The body emits heat through, among other things, the flow of heat from the skin and clothing to the colder air in the environment, radiation from the skin and clothing on colder surfaces in the environment, evaporation of water from the skin and evaporation of water during respiration.

The body’s heat production depends on physical effort. In hard work it is about three times greater than in light work.

Changes in air temperature are usually the first thing people notice. If it is too cold in the work space, the body responds by increasing muscle tension. As a result, your metabolism increases and your body temperature remains stable. It becomes more difficult to move your fingers, workspeed decreases and the risk of mistakes increases.

If it gets too hot in the work area, the muscles relax and sweating increases. As soon as the temperature is a few degrees above what is considered comfortable, many people experience drowsiness. This reduces both mental and physical skills. The likelihood of mistakes, discomfort and headaches increase.  High temperatures can also have a negative effect on other factors and people generally feel that the air quality is worse when the temperature is too high.

A suitable temperature for sedentary work is considered to be 18°–22°C, but for jobs where work is performed standing without much movement, the comfort criteria is 16°–18°C. Some jobs may require lower temperatures due to production, in which case staff must be provided with special clothing and time limits in cool work spaces.

Most people find it most comfortable if the temperature is 20-22°C when sitting still, but for some, higher temperatures or up to 24°C are comfortable.

It is important to keep in mind that people generally feel uncomfortable if the temperature changes during the day exceed 4°C. Temperature changes can be greater when there is a lot of electrical equipment and where screens are not used to protect against the sun’s heat through windows.

Some places in the workspace will be uncomfortably cold, for example where insulation is inadequate and directly under the inflow of air from mechanical ventilation. It is not advisable to have a work area near large windows. In winter, cold window panes can cause cold air to descend, leading to draft and cold feet.

If it is not possible to avoid having a work area by the window or exit door, measures should be taken to reduce the inconvenience that the location may cause, for example placing portable heaters under windows and erecting a windbreak at the exit door to reduce the inflow of cold air, not least if heated air is directed there.

The reason why drafts often cause discomfort is the interplay of heat and movement in the air. Movement in the air is then greater than about 0.15 m/per second during sedentary work. The moving air is colder than the air in the room. This also applies to slow air currents. It can also be cold radiation, for example if some heat is transmitted from people onto colder surfaces. If it is significant, people will feel like there is a draft, even though there is no noticeable movement in the air.

Drafts mainly affect those who work sedentary jobs. Over time, drafts can cause discomfort in the muscles and joints. In addition, constant cooling of the skin can reduce the body’s resistance to various pests.

Many things can cause drafts, including leaky windows and inefficient ventilation systems. Many measures can be taken to prevent drafts, such as sealing doors and windows, adjusting ventilation systems and maintaining them well, and designing housing in such a way that work spaces are not very large, as it is easier to control air quality in smaller spaces.

Humidity refers to the relative amount of water vapor in the atmosphere. It is measured and expressed as a percentage of the amount of moisture that can be in the air at a given temperature. If the temperature rises, the air can store more water vapor. In cold air there is almost no water vapor. Therefore, the humidity is low indoors during the winter. Cold air enters and is heated, if moisture (water vapor) is not added to it, the humidity of the air decreases.

In general, humidity does not cause discomfort. However, low humidity can cause irritation to the eyes, lips and respiratory system, especially if the air is too hot and dusty. In addition, dry air contributes to the generation of static electricity.

Extremely humid indoor air can lead to the formation of damp spots on walls, windows and ceilings, which can contribute to mold formation. That increases the risk of discomfort due to allergies and intolerances.

Outdoor humidity can fluctuate throughout the year from about 20% relative humidity (rH) in winter to up to 60% in summer. People usually do not experience changes in humidity if the temperature is between 20-22°C. If the temperature exceeds 24°C, most people will feel like the air is heavy and stifling if the humidity is also above 50% rH.

No criteria have been set for humidity in the workplace, but most people feel best at 30-60% rH. To prevent too dry or too humid air, the humidity should be kept between 30-50% rH.  With rising temperatures and increased workload, the effect of humidity on an employee’s well-being increases. The higher the humidity, the higher the temperature appears to be. If there is a lot of dust in the air, it may seem dry, even when the humidity is within normal limits.

Where humidifiers are used to increase air humidity, extreme hygiene must be maintained, water renewed and the humidifier cleaned regularly to prevent the release of micro-organisms, including germs and mold. Employees often feel better if they use small humidifiers on desks and in individual workplaces, but it is important to keep them clean so that they do not breed microbes and dirt.

Carbon dioxide (CO₂) is a colorless, odorless and non-flammable gas with a slight acid taste at room temperature. It is a by-product of the burning of substances as well as being formed by the metabolic processes of organisms, such as humans. Since CO₂ formed by exhalation, its concentration in spaces is used to indicate whether sufficient fresh air is supplied into the space.

High concentration of carbon dioxide (>0.1%) may cause headache and fatigue, but nausea, dizziness and vomiting if it exceeds the exposure limit (>0.5%). If the concentration is very high (>1%) it can lead to unconsciousness. In general, 20% of people complain of stuffy air if the concentration of CO₂ over 1,000 ppm. According to the Building Regulations it must be ensured that the amount of CO₂ in indoor air will not normally exceed 0.08% and will not exceed 0.1% CO2 in the short term.

To prevent or reduce high levels of carbon dioxide in a building or  a room, fresh air should be supplied to the area, for example by opening windows.

VOC is an abbreviation for the term “Volatile organic compound” and is a synonym for thousands of organic compounds that contain carbon and are mainly gases at room temperature. VOCs are common due to the use of paints, varnishes, polish, detergents and fragrances but can also come from furniture, appliances and equipment.

These volatile substances evaporate easily and assimilate into the indoor atmosphere. The most common VOCs in the atmosphere that people are at risk of inhaling are acetone, arsenic, benzene, ethylene glycol, formaldehyde and hydrogen sulphide, many of which are carcinogenic.

There are no approved exposure limits for VOCs or a total limit for volatile organic compounds, but it is generally believed that if the concentration in the atmosphere is below 90 pbb (parts per billion) it is considered low, 90 – 150 ppb acceptable, 150 – 310 ppb on the verge of being bad and high if it exceeds about 310 ppb.

Good ventilation is the key to keeping the concentration of these substances down.

Fine dust in indoor air is classified into two types, PM2.5 and PM10, but PM is the English term for “particulate matter”. It is a mixture of solid particles and droplets, for example dust, dirt, soot or smoke particles that are so large and dark that they are visible to the naked eye. Others are so small that they can only be detected under an electron microscope.

• PM10: Inhalable particulate matter, usually 10 micrometers (0.01 mm) in diameter and smaller.
• PM2.5: Fine inhalable particulate matter, usually 2.5 micrometers (0.0025 mm) in diameter and smaller. The figure below shows the size ratios of the particle sizes.

Because these particles are so small, they are easy to inhale. Some particles are less than 10µg in diameter and can get deep into the lungs and some even into the bloodstream. Particles smaller than 2.5 µg (PM2.5) in diameter are the most dangerous.

Exposure limits according to the regulation on exposure limits and measures to reduce pollution in the workplace for very fine dust is 10 mg/m³.

There are no approved indoor limit values for PM10 and PM2.5 in particular, but some manufacturer’s testing equipment set the target >15/g/m³.

Good mechanical ventilation with clean filters and air purifiers contribute to dust-free indoor air.

When measuring indoor air quality (IAQ), an attempt is made to assess the temperature and its effect, as well as other environmental factors. Measuring IAQ has a number of challenges. Measuring only individual factors, for example temperature, can give a misleading result because it says little about the overall effect. For example, it depends on air speed, humidity, and what kind of work takes place whether people feel the temperature is suitable.

It is important to do a preliminary study and find out how employees experience the air indoors and what could be causing the discomfort they may be complaining about.

Examples of questions:

• How is the workplace heated?
• Are spaces free of drafts?
• How well are they cleaned?
• How well does the ventilation work?
• Are the spaces suitably large?
• Is there a variety of physical effort involved in the work?
• To what extent is it possible to control the effects of indoor air quality where the work is performed?

These are the main things that employers, security guards, security employee representatives and other staff can usually evaluate themselves.

The list below could be considered with expert assistance. The following air quality factors are always taken into consideration when conducting a thorough indoor air quality inspection:

• Air temperature
• Heat radiation
• Air speed
• Humidity
• Carbon dioxide (CO₂)
• Volatile Organic Compounds (VOCs)
• Fine dust (PM2.5)

It is important that measuring equipment is used in accordance with the instructions and are calibrated correctly. The location of the measurements, distance from the floor and time of day greatly influence the results. The weather must also be considered and outdoor air measurements might be performed that can affect the result of indoor air measurements.

The location of a building affects the indoor air in it. If there are a lot of heavily trafficked streets nearby, there may not be proper ventilation. This can be due to both pollution from emissions and the disturbance caused by traffic noise.

In buildings in such places, the inlet for mechanical ventilation shall be placed at the highest possible height in order to prevent indoor air problems.

It is best to reduce noise at the source. The closer a solution to a noise problem is to the noise source, the better the solution. Therefore, the best solution is to prevent noise from happening. Then you work your way away from the noise source towards those who are exposed to unwanted noise.

1. Solve the problem at the source of the noise, for example by fixing or lowering engine noise
2. The structure of noise source
3. Partitions
4. Reduce reverberation time – Reduce echoes
5. Shorten the presence of employees in noise – the organization of work
6. Hearing protection – these are emergency measures that are used while looking for other solutions)

There are two types of hearing protection:

• Earplugs, which are placed in the ear canal
• Ear muffs that cover the ear

As soon as work that may cause hearing damage begins, the employer or his representative is obliged to ensure that employees wear hearing protection. This means that even working at noise levels of less than 85 dB(A) may require the use of hearing protection.

Hearing protection is not a permanent solution to a noise problem. Efforts shall be made to reduce noise at its source.

If, in certain cases, for technical or administrative reasons, it is not possible to reduce the noise exposure for employees below the 85 dB(A) limit, the employer or their representative shall only allow the work to be carried out if hearing protection is used.

If the noise level of the employees is 80 dB (A) or the noise is harmful or significantly disturbing, then the employer must provide the employees with hearing protection. This can be in cases such as where very noisy work is performed for a short time or where there are loud percussive noises. Employees should be given hearing protection in such cases even though the noise exposure is less than 80 dB(A).

Where noise exposure for employees exceed 80 dB(A), employees should wear hearing protection. Otherwise, they risk damaging their hearing.

Hearing protection can make it difficult for employees to talk to each other and thus isolate them from the environment. This must be borne in mind in order to prevent any possible danger as a result. Hearing protection that muffles the noise much more than needed can thus isolate the user and increase the risk.

The employer shall ensure that:

• Employees receive appropriate hearing protection, which do not cause discomfort
• Employees receive instructions on how to use the hearing protection and information on the danger of not using them. The instructions should relate to the use/optimization, cleaning and storage of the hearing protection.
• The hearing protection should be properly maintained

The employer provides and pays for the hearing protection and they are the property of the employer. The hearing protection is for personal use and others should not use them.

Hearing protection can cause discomfort due to heat, pressure, skin irritation and rash. The discomfort can be individual, so it is important that staff have access to different types of hearing protection and can thus choose the ones that are comfortable but also provide good protection.

An employee is obliged to use hearing protection if the job is of such a nature that it is not possible to protect the employee’s hearing in any other way.

The main measurements performed at workplaces are as follows:

Noise Dosimeter Measurements

A microphone is placed as close as possible to the ear of an employee who wears the meter during the working day, or part of the working day. The results of these measurements give a very clear picture of the noise exposure experienced by the employee in question or equivalent noise based on an eight-hour working day, noise peaks and even background noise.

Sound Level Measurements

SLM is commonly a hand-held instrument with a microphone to test noise at certain spots at a specific noise source or at a specific workplace. These measurements are usually short. The meter does not follow the employee, but if the employee has a permanent workstation all day and the noise is relatively equal, a local measurement can indicate the noise that the employee is exposed to.

Frequency Weightings

Frequency weightings are actually local measurements that measure noise at different frequency ranges. These measurements are done to determine if it is a high-frequency or a low-frequency sound. Usually for the purpose of finding suitable solutions, because the same solutions for low-frequency noise and high-frequency noise are not always sufficient.

Reverberation Time Measurements

Reverberation time is an indication of echo. More echo means a longer reverberation time. Echoes are in fact a reverberation of sound and as a result the noise is amplified by increased echoes and the acoustics deteriorate.  Reverberation time measurements are therefore made to assess the acoustics and provide criteria for calculations for improvements.

There is reason to be alert for symptoms such as:

• Numbness in fingers
• Loss of feeling in fingers and hands
• Loss of strength or weakness in hands
• The fingers whiten due to vibration, but when at rest they blush with a feeling of pain.
• Difficulty with fine motor skills
• Discomfort and pain due to cold and humidity
• Impaired grip strength

These symptoms are more likely to occur in cold and humidity and at first probably only at the front of the fingers.

There is reason to be alert for symptoms such as:

• Visual disturbances
• Equilibrial disturbances
• Discomfort related to the musculoskeletal system
• Pain, stress, sleep disturbances
• Damage to internal organs

If working continuously in vibration, the effect can be permanent.

To fight against vibrations, a variety of solutions can be applied. These include:

• Changed working methods, where employees are less exposed to mechanical vibration
• Appropriate choice of work equipment, which is ergonomically designed and produces the least possible vibration with respect to the work to be performed,
• Accessories that reduce the risk, such as seats that significantly reduce vibration throughout the body and handles that reduce the transmission of vibration to the hands and arms,
• Appropriate maintenance plans for work equipment, workplace. Choice of driving routes and surface
• Information and training to teach workers to use work equipment correctly and safely and to keep mechanical vibration to a minimum, as well as to examine sitting position and body posture and adjustments of seats and even controls.
• Reasonable working hours with appropriate rest periods, limiting the time that employees experience vibration and reducing vibration
• Protective clothing, among other things, to protect against vibration and cold and humidity
• Whether the harmful effects of vibration throughout the body could remain outside working hours is the responsibility of the employer
• Special working conditions, such as low temperatures